Control switch



April 13 1937 o. F. cARLsoN 2,076,546

CONTROL sw'rcH Filed oct. 4, 1935 :s sheets-sheet 1 April 13, 1937. o. F. CARLSON 2,076,546

CONTROL SWITCH Filed Oct. 4, 1935 5 Sheets-Sheet 2 D D Q I@ S kg (U Y (G. .j N m l Q' Si. g an) L Q' S Qg/ J" un f 1 V im l l L' @h rl@ y Oscar Cal/5072*I April 13, 1937- o. F. CARLSON 2,076,546

CONTROL SWITCH I Filed Oct. 4, 1935 l 3 Sheets-Sheet 3 Patented Apr. i3, 1937 UNITED STATES PATENT. OFFICE CONTROL SWITCH Application October 4, 1935, Serial No. 43,564

19 Claims.

This invention relates to control switches, and more particularly is directed to a control switch responsive to the level of water in a boiler, or to the level of oil in a fuel supply tank for a burner 5 or the like, and also responsive to the development of excessive pressures in the boiler or tank, for actuating an alarm circuit and for cutting off the burner motor or heating means if the pressure condition is not corrected.

l In the copending application of Alfred W. Shepherd, Serial No. 36,447, led August 16, 1935, there is disclosed a level control switch corresponding to that of the present invention, and the present invention comprises an extension of the l underlying principles of that application to provide a switch capable of responding to both level and pressure.

The preferred form of the present invention is directed to a float chamber which may be suitably supported at any desired level, containing a sealed float member having flexible hollow supporting means, with a switch carried within the float and responsive to tilting of the float for controlling operation of any desired electric circuit.

l5 The tilting of the float can be accomplished either by lowering of the liquid level, or by predetermined increase in pressure within the float chamber.

One object of the present invention is to provide a float controlled switch responsive to both liquid level and pressure.

Another object of the present invention is to provide an adjustable pressure control which in no way influences or interferes with the operation of the switch responsive to liquid level.

A further object of the present invention is to provide a control switch structure in which a float completely encloses a switch member, the float being responsive to both pressure and liquid level control, with the switch responding in like manner to both conditions.

Other objects and advantages of the present invention will appear more fully from the following detailed description, which, taken in conjunction with the accompanying drawings, will disclose to those skilled in the art the particular construction and operation of a preferred form of the present invention.

In the drawings:

Figure 1 is a diagrammatic view showing one manner in which the control switch of the present invention may be employed;

Figure 2 is a vertical sectional view through the 66 control switch shown in Figure l;

Figure 3 is an end elevational view of the switch shown in Figure 2;

Figure 4 is an enlarged sectional view through the pressure adjusting means, taken substantially on line 4 4 of Figure 2;

Figure 5 illustrates a modified form of means rendering the switch mechanism pressure responsive; and

Figure 6 is a section taken at an enlarged scale along the line 6-6 of Figure 5.

Referring now in more detail to the drawings, I have indicated at 5 a heater, such as a boiler or the like, provided with a. suitable burner mechanism 6 operated by the motor 1, the burner and motor being supported upon a suitable stand 8. Obviously any desired type of burner mechanism v may be employed.

The boiler 5 is provided with a gauge glass 9 for indicating the level of water in the boiler compartment, and connected to the lower fitting lll of the gauge glass is an extending pipe II which is connected to the float housing I2. The float housing I2 is also connected through the pipe I3 to a suitable blow-oil. valve I4 mounted at the upper end of the boiler 5.

Considering the detailed construction of the float control switch, the switch structure is, in the main, similar to that shown in the copending Shepherd application above referred to, comprising a housing I6 provided with a tapped opening I1 into which the pipe I3 is connected, and also provided with the tapped opening I8 into which the extension pipe II is fitted. The housing I6 is also provided with the tapped outlet I9 to which a suitabledrain valve 20 may be connected, if desired.

The housing I6 is adapted to be closed at its end by a disc or plate member 2II sealed about the end of the housing by means of the gasket 22. The disc 20 at its central portion is provided with an opening to which is sealed the inner end 23 of a, hollow flexible bellows member 24, which has its outer end 25 secured to a plate 26 forming the closure for one end of a oat member 21, which at its opposite end is closed by the cap member 28.

Disposed within the float 21 is a mercury switch member 29, which is supported in fixed position by means of the clip members 30 connected together through the bracket member 32 and secured on the interior side walls of the float to maintain the switch 28 in xed position within the float, as clearly shown in Figure 3.

The leads for the switch, indicated at 33, extend rearwardly through the interior of the bellows 24 outwardly of the disc 26. The disc 20 is clamped to the rear end of the housing I6 by means of a clamping plate having a channel faced annular ring portion 34, and provided with a plurality of clamping screws 35. Supported on the plate is an insulating disc 36, carrying suitable bushings 31 to which the ends of the leads 33 are connected through metal contact clips 3l.

'I'hese bushings 31 are adapted to receive suitable terminal lugs 38 and terminal screws 39 for securing conductors thereto to lead the circuit outwardly of the switch.

The terminal lugs 38 are formed from metal stampings having inturned ends 40 adapted to l5 seat in suitable recesses formed in a second insulating disc 42. A suitable separator 43 is interposed between the opposed pairs of lugs.

Enclosing the terminal plates 36 and 42 is a metal closure member 44 forming an outlet box 45 at the rear end of the switch housing, and which is provided with a cylindrically flanged portion 46 engaging the peripheral edge of the plate 20. The member 44 is secured to the housing i6 by means of a plurality of screws 41 passing through the ange 46. A suitable closure plate 48 is secured to the housing 44 by means of the screw 49 and provides a rectangular box at the rear end defining the chamber 45. A suitable opening 5U is provided for leading out the cable or conduit containing the conductors connected to the respective terminal screws 39.

The operation of the control switch as described up to this point corresponds to the operation of the switch shown in the copending Shepherd application, that is, upon lowering of the float 21 due to lowering of level within the float chamber i5, the oat tends to rotate about the bellows 24, flexing the bellows, until the reinforcing ring 52 of the float engages the integral stop 53 formed in the housing I6. At this time, the switch 2S operates to close an alarm circuit, to shut oli a burner motor, or to perform any similar function, such as opening a feed water control valve or the like.

The present invention particularly resides in the provision of a tapped opening 54 provided in the upper surface of the housing i6, which is adapted to receive the threaded bushing 55, the bushing 55 carrying a regulating pin 56, which 5o pin is provided at its upper end with a collar or flange portion 51 limiting its downward movement with respect to the bushing 55, and with a head 58 having a suitable kerf 59 formed therein for receiving a screw driver or similar 55 member for rotating the pin 56. A suitable cap nut 60 threads over the upper end of the bushing to enclose the head 58 of the pin 56, preventing accidental movement of the pin, and the engagement of this cap nut with the flange 51 60 of the pin seals the pin by engagement against the upper surface of the bushing 55, preventing leakage therefrom.

The lower end of the pin 56 extends into the interior of the housing I6 and is provided with an annular grooved portion 62 receiving the eccentric ring member 63 which is adapted to have abutting engagement with the rear edge of the oat 21, as indicated at 64. This engagement is shown in more detail in Figure 4. By

rotating the pin 56, it will be apparent that the outer periphery of the disc 63 will move toward and away from the rear edge of the oat 21, whereby upon ,increase of pressure within the housing i6 the bellows 24 Will be compressed,

moving the rear edge of the float into abutting amano engagement with the ring 63, as indicated at 64.

Further movement of the upper end of the float is thereby prevented, and upon further increase of pressure the float rocks downwardly in the same manner as when the level of liquid within the chamber is reduced. Thus, upon predetermined increase of pressure, the float rocks about the point of engagement 64 with the pin in a downward direction to produce actuation of the switch 29. The adjustment of the pin 56 will produce operation of the float at any predetermined pressure, by providing a predetermined movement of the oat before the engagement of the rear edge thereof with the disc 63.

Considering now the circuit shown in Figure l, a transformer 65 is provided, the secondary of which is connected through one conductor 66 to one electrode within the mercury tube switch 29 supported in the float 21. The other conductor of the secondary winding of the transformer 65 is connected to the burner motor and to one side of a control circuit for an alarm device 61. The other electrode of the switch 28 is connected through the conductors 68 and 69 to the burner motor and the control circuit for the alarm device, respectively.

The control circuit for the alarm device comprises a conductor 69 having a relay 10 in the circuit thereof, which relay is adapted to normally maintain the circuit through the alarm device unenergized, but upon deenergization of the circuit through the relay 1U the armature 12 thereof drops down to close the circuit through the alarm device, thereby actuating the alarm. At the same time the motor is shut oil.

Thus, if the water level in the boiler drops below a predetermined point, the alarm device is sounded and the burner motor is shut off. Also, if the pressure within the boiler builds up beyond a predetermined point, the alarm device is sounded and the burner motor is shut orf. It is therefore apparent that I have provided a control switch which may be operated either by variations in level of water in a boiler or the like, or by variation in the pressure to which the switch is subjected, thus preventing operation of the burner motor under low water or high pressure conditions, and which simultaneously is capable of actuating an alarm to indicate the pressure of a dangerous condition.

By virtue of the adjustable means described above, the float controlled switch is rendered responsive to pressure within the housing i6. In Figures 5 and 6 I have illustrated another means for securing the same result, embodying a separate pressure responsive bellows mounted exteriorly of the housing i6 on a fitting 8| adapted to be threaded into the casing opening 54. The pressure responsive bellows 8D is sealed at its lower margin to the fitting 8l and has its interior in communication with the interior of the float housing i 6 through a central opening 82 in the fitting or bushing 8i. The bellows 80 includes a sealed head in the form of a rigid plate to which a bracket 86 is secured interiorly of the bellows.

A forked member 90 is pivotally connected at its upper end to the bracket 86, and the lower bifurcated end of the member 90 includes arm sections 9| partially embracing the bellows 24, being disposed on opposite sides thereof and carrying suitable pivots 92 or the like on which rollers 93 are rotatably mounted. The rollers 93 bear against a rectangular plate member or flange 94 Cil secured to the bellows end of the oat 21, and

a pair oi' thrust links 91 and 98 are mounted on the pivots 92 and at their other ends are pivotally anchored to brackets Il secured to or car- 5 ried by a plate Ilil.

In its generic aspects, the operation of the above means rendering the iloat 21 responsive to pressure is substantially the same as that set forth above in connection with Figures 1 to 4. l0 Since the bellows III is in communication with the steam space of the iloat housing I9, the bellows expands and contracts in response to pressure changes. For example, at or below the desired normal pressure, the member 90 stands at the position indicated in Figure 5 with the rollers 93 substantially at the center of the plate 94 and the iloat 21. In this position the pressure within the casing i6 reacts through the links 91 and 93 directly against the plate |00, but does not tilt the lloat, the bellows 24 being relieved thereby of any tendency to become collapsed. However, the connection between the member 90 and the iloat 21 is such that the rocking of the latter in response to liquid level changes, is not 25 yinterfered with, and hence the unit remains fully responsive to the water level in the housing I6. When the pressure within the housing or casing I6 becomes abnormally high, the bellows 90 is expanded, the head 85 moving upwardly and carrying with it the member 90. The upward movement of the latter carries the rollers 93 above the center of the plate 94, and as soon as the rollers 93 move thus into an eccentric position the pressure within the casing i6 immediately becomes eilective to rock the oat 21 downwardly in substantially the same manner that the interior pressure acts in the construction shown in Figure 2 to tilt the float so as to operate the switch means enclosed therein. Since the bellows 80 moves to different positions in response to different pressures within the casing I6, the unit shown in Figure 5 is quite sensitive in that the greater the abnormal pressure, the more quickly will the float 21 be tilted, due principally to the greater eccentricity of the rollers 93.

Since the bellows 80 forms the pressure sensitive means, the sealing bellows 24 can be made very flexible. If desired, suitable biasing means, such as a. spring, may be employed with the bellows 80, and if such spring means, or the bellows, is made adjustable, the unit may be arranged so as to provide for the oat 21 tilting at various pressures.

Having described my invention in accordance with the patent statutes, what I claim as new and desire to secure by Letters Patent is:

l. In combination, a iloat chamber, a float therein, a flexible bellows supporting said float for both pivotal and axial movement in said chamber, a switch in said iloat having leads extending outwardly of said chamber through said bellows, and means serving as an abutment adapted to be engaged by the float in eccentric relation so that upon c ollapsing of said bellows due to pressure in said chamber said oat is moved into switch actuating position.

2. In combination, a float chamber, a float therein, a flexible bellows supporting said oat for movement in said chamber, a switch in said iloat having leads extending outwardly of said chamber through said bellows, and a member engaged by said iloat in eccentric relation upon the attainment of a predetermined pressure in said chamber for collapsing said bellows and rocking said oat about its point of contact with said membersoutomovenidtloatintoswitch actuating position.

3. In combination, a iloat chamber, a float therein, a flexible bellows supporting said iioat for tilting and axial movement in said chamber, abutment means normally reacting 'against the central portion of said oat for preventing axial movement oi' the latter while providing for the tilting movement oi' the iloat, pressure responsive means for eccentrically shifting said point of reaction so as to cause the pressure within said chamber to tilt said iloat and control means disposed to 'be operated in response to changes in position of said iloat.

4. In combination, a iloat chamber, a float therein, a flexible bellows supporting said iloat for movement in said chamber, a switch in said float having leads extending outwardly of said chamber through said bellows, and an adjustable member disposed to be eccentrically engaged by said oat upon collapsing of said bellows due to pressure in said chamber for cocking said oat into switch-actuating position.

5. In combination, a iloat chamber, a hollow oat therein supported by a flexible bellows member and adapted to ilex said bellows during variations in liquid level in said chamber, a mercury switch supported in said float and having terminal connectons extending outwardly of said chamber through said bellows, and means disposed to be eccentrically engaged by said float upon predetermined increase in pressure within said chamber for cocking said iloat into switchactuating position.

6. In combination, in a float chamber having an apertured disc sealed to one side thereof, a flexible bellows sealed in said aperture and extending into said chamber, a hollow iloat sealed to and communicating with the interior of said bellows, a gravity operated switch in said iloat having terminal connections extending outwardly through said bellows and disc, and means disposed to be eccentrically engaged by said float upon predetermined increase of pressure within said chamber for cocking said iloat into switchactuating position.

7. 'I'he combination with a float chamber having a sealed hollow iloat therein supported by a flexible bellows, and a gravity-operated switch in said float, of means for operating said float into switch-actuating position upon increase of pressure in said chamber comprising an abutment vmember projecting into said chamber and disposed to be eccentrically engaged by said float upon said increase of pressure to cock said iloat out of normal position. y

8. The combination with a iloat chamber having a sealed hollow float therein supported by a ilexible bellows, and a gravity-operated switch in said iloat, of means for operating said float into switch-actuating position upon increase of pressure in said chamber comprising an abutment member projecting into said chamber and disposed to be eccentrically engaged by said iloat upon said increase of pressure to cock said oat out of normal position, said means having a portion projecting out of said chamber for adjusting the pressure at which said iloat will be operated. 9. A float chamber having an opening in one side wall thereof, a ilexible bellows supported at one end within said opening, a oat secured to the opposite end of said bellows and communieating with the interior thereof, a switch supported within said float and actuated by tilting of said iloat due to lowering of liquid level in Cil said chamber, and means for tilting said oat independently of said liquid level upon a predetermined increase of pressure in said chamber.

10. A float chamber having an opening in one side wall thereof, a flexible bellows member projecting into said chamber through said opening, a float supported on the inner end of said bellows, a gravity-operated switch in said float. a pin projecting into said chamber adjacent the inner end of said bellows, and an eccentric disc carried by said pin and disposed to be eccentrically engaged by said float upon collapse of said bellows for tilting said float into switch-actuating position.

11. A float chamber having an opening in the top wall thereof, a bushing in said opening, a pin extending through said bushing into said chamber, a float in said chamber having a gravityoperated switch therein, flexible pressure responsive means supporting said float from the side wall of said chamber, and means on said pin eccentrically engaging a portion of said float upon contraction of said pressure responsive means for tilting said float into switch actuating position.

l2.V The combination with a float chamber of the class described including a iioat having an expansible and contractible support for allowing tilting of said float upon lowering of liquid level in said chamber, of means disposed to eccentrically react on said lioat for effecting corresponding tilting thereof upon contraction of said support under a predetermined pressure and control means disposed to be operated in response to changes in position of said oat.

13. The combination with a hollow float member having a exible supporting bellows at one end thereof and adapted to tilt about said bellows in response to variations in liquid level, said bellows beng contractible under increases in pressure, of means eccentrically engaging a portion of said float as said bellows contracts for tilting said float about said bellows and control means disposed to be operated in response to changes in position of said float.

14. In a oat chamber, a iloat member having a exible hollow support in one side wall of said member, and means for limiting horizontal movement of said iloat in said chamber comprising a pin extending into said chamber, cam means at the inner end of said pin for engaging a vertically extending portion of said float to prevent lateral movement thereof, means at the outer end of said pin providing for adustrnent of said cam means and control means disposed to be operated in response to changes in position of said oat.

15. In combination, a oat chamber, a float therein, a exible bellows supporting said ont for angular movement in a vertical direction in said chamber, a switch in said oat having leads extending outwardly of said chamber through said bellows, an adjustable member adapted to engage said oat in one position so as to resist any axial movement of said float, and a bellows operatively connected .with said member and resposive to the pressure within said chamber for moving said member into a position rendering the pressure within said chamber effective to rock said float into switch actuating position.

16. A combined liquid level and pressure responsive device comprising a float chamber, a float movably mounted therein, a flexible bellows operatively connecting said float with said chamber for both axial and vertical angular movement, switch mechanism mounted on the interior of said float and actuated by the angular position of the latter, and a pressure sensitive unit responsive to the pressure within said float chamber and eccentrically reacting at a point against said float so that upon the occurrence of a predetermined pressure within said float chamber said float rocks about said point of reaction to actuate said switch mechanism.

17. A liquid level and pressure responsive device comprising, inA combination, a float chamber disposed to be connected to a container of a liquid under pressure, a float in said chamber, means for effecting the rotation of said iioat about different centers in response to change in level or pressure of said liquid, and electric switch means carried by said float and disposed to be operated in response to change in position thereof.

18. A liquid level and pressure responsive device comprising, in combination, a float chamber disposed to be connected to a container of a liquid under pressure, a float in said chamber, means for effecting the rotation of said float about one axis in response to change in level of said liquid, means for effecting the rotation of said iloat about another axis in response to change in pressure, and control means disposed to be operated in response to change in position of said iloat caused either by change in level or pressure.

19. A liquid level and pressure responsive device comprising, in combination, a float chamber disposed to be connected to a container of a liquid under pressure, a float in said chamber, means for effecting the rotation of said float about one axis in response to change in level o said liquid, means for effecting the rotation of said float about another axis in response to change in pressure, and electric switch means carried by 

